The invention relates to a coding and decoding process making it possible to reduce the information quantity of a television image or picture in order to facilitate its transmission or storage. This process more particularly makes it possible to code and decode a single picture, such as that analyzed by certain cameras on board aeria reconnaissance aircraft, a scan or sweep being performed on the one hand by the movement of the aircraft and on the other by a linear optical sensor analyzing a single line and which can be constituted by a plurality of charge coupled devices (CCD), which are placed end to end. Such a camera consequently analyzes a single picture having an infinite number of lines. In this case, inter-image or inter-frame coding methods cannot be used.
Various adaptative coding processes are known, which code the brightness values of a picture in point-by-point manner or by constant brightness ranges using the redundancy of brightness informations in the same line or frame. However, the process according to the invention makes it possible to obtain a much better information compression level.